Find where hail hit, how big it was, and which addresses to knock — fast.
SwathIQ turns NOAA radar (MRMS MESH) into an interactive hail map going back to 2010, with live updates during active storms. This guide covers everything from reading the map to building a door-knock list.
Pick a date. Use the date box at the top (or the arrows / ← → keys). The Recent storms list on the left jumps you to the biggest recent hail days. Dates are UTC days — a late-evening storm can land on the next day's data.
2
Read the swath. The colored overlay is the radar-estimated max hail size for that day. Warmer/darker = bigger hail (see the scale in the left panel).
3
Click anywhere to see the exact hail size at that spot plus a plain-English damage read.
4
Build a list. Use Hailed addresses (30 mi) to map every street address near your click that got hail above your threshold, then download it from the Export tab in the right-hand dock (by ZIP or street + radius, CSV).
Reading the hail map
The MRMS swath overlay
The main colored layer is MRMS MESH — NOAA's radar estimate of the largest hail that fell in each ~1 km cell that day. It's an estimate from radar, not a ground measurement, so treat it as "where hail most likely fell and roughly how big."
Color
Rough hail size
What it means for roofs
Yellow
~0.75–1″
Quarter-size. Granule loss / bruising possible — worth an inspection.
Orange
~1–1.5″
Likely functional damage on softer roofs.
Red
~1.5–2″
Widespread damage likely; strong claim territory.
Purple
2″+
Severe. Full replacements common.
Controls (left panel)
Overlays — toggle the MRMS swath, SPC hail reports (ground-truth dots), wind reports, tornadoes, and the NEXRAD radar loop.
Swath opacity — fade the overlay to read streets underneath. The swath also auto-fades as you zoom in, so streets/parcels stay readable at neighborhood level.
Base map — switch between Streets and Satellite.
Min hail at property — hide cells below a size so you only see what matters.
Swath vs. hail reports: the swath is a continuous radar estimate everywhere; the SPC hail-report dots are individual human/storm-spotter reports. Use the reports to corroborate the radar.
Click any point
Click anywhere on the map (or just hover) to read the exact MESH hail size at that spot for the selected date, shown in the inspector with a roofer-readable verdict (e.g. "1.25″ — widespread damage likely"). A pin drops at the point. This works for any logged-in account.
Hailed addresses (30 mi) Trial & paid
The fastest way to turn a storm into a canvassing list:
1
Open the Hailed addresses (30 mi) control in the left panel, pick a minimum hail size (1.0″ / 1.5″ / 2.0″), and click Pick a point on the map.
2
Click where you want to work. SwathIQ draws a 30-mile circle and pulls every street address inside it whose hail that day met your threshold — colored by hail size, closest to your click first.
3
Hover a dot for the address + hail size. To take the whole list into your CRM or routing app, open the Export tab in the right-hand dock and download the addresses as a CSV (see Address export below).
These are public street addresses (so you know where to go) — they do not include homeowner names or phone numbers. Contact data is part of the paid leads product. Scoped trial/customer accounts only see addresses inside their entitled states.
Address export (dock) Trial & paid
The Export tab in the right-hand dock is your self-serve way to download a CSV of hailed addresses. It pulls street addresses only — no homeowner names or phone numbers — and stays inside your entitled markets and export allowance.
1
Open the Export tab in the dock and pick how to scope the list: by ZIP code, or by street name + radius around a point.
2
Optionally turn on the hail-hit filter to keep only addresses that took hail in the last 3, 6, or 12 months.
3
Hit Preview to see the count and a sample, then download the full list as a CSV. Exports are capped by your account's allowance and scoped to your entitled markets.
The Export dock returns addresses, not contact-enriched leads. For lead lists with homeowner contact data, use Request export (see Exports & leads below).
Storm alerts
Click Get storm alerts to be emailed or texted (or pinged in Slack) the moment hail hits the markets you care about. Pick states/ZIPs and a minimum size; you can unsubscribe anytime from any alert.
Exports & leads Trial & paid
SwathIQ has two kinds of export, and they work differently:
Address exports (self-serve). Download a CSV of hailed street addresses yourself from the Export dock — by ZIP or street + radius, with an optional 3/6/12-month hail-hit filter. These contain no homeowner names or phone numbers, and are scoped to your entitled markets and export allowance.
Lead lists (by request). Lead lists are addresses enriched with homeowner contact data — a paid deliverable. They are not self-serve: open the account menu and choose Request export. Your request goes to our team, who reviews it and delivers the list to you. The per-date and per-range lead CSV controls inside the dock are admin-only.
All exports are capped per account and scoped to your entitled markets.
FAQ
What is MESH / MRMS?
MRMS (Multi-Radar Multi-Sensor) is NOAA's national radar mosaic. MESH = Maximum Estimated Size of Hail — a radar-derived estimate of the biggest hail in each grid cell. SwathIQ shows the 24-hour max MESH per day.
How accurate is it?
It's a radar estimate, not a ground measurement, so it can over- or under-shoot in any given spot (and raw radar has some false signals over oceans/mountains that we filter out). Use the SPC hail report dots to corroborate, and treat the swath as "very likely hailed, roughly this big." It's excellent for prioritizing where to canvass.
How fresh is the data?
Historical coverage goes back to 2010. During active weather it updates roughly every 5 minutes (look for the LIVE chip). Because dates are UTC days, a late-evening US storm may show up on the following calendar day's map.
Are these addresses my "leads"? Do they include names/phones?
No. The addresses come from public address data so you know which houses got hit. Homeowner names and phone numbers are part of the paid leads product, not the free/trial address view.
How do I use it to canvass / door-knock?
Find the storm day, click into the impacted area, run Hailed addresses (30 mi) at your minimum size, then download the addresses from the Export tab in the dock (by ZIP or street + radius) and load the CSV into your routing/CRM. Bigger thresholds (1.5–2″) give you the highest-damage doors first.
A date shows no hail — why?
Either no significant hail fell that UTC day, or the storm crossed the midnight-UTC boundary — try the day before/after. The Recent storms list always points to days that actually had hail.
What's the difference between a trial and a paid account?
Trials get scoped, time-limited access (your entitled states) to the map, click-inspect, the hailed-addresses tool, and the self-serve address export (capped by your allowance). Paid accounts add larger allowances and access to lead lists with homeowner contact data, delivered via Request export.
Can I share or embed a view?
Open the map at your date and location and share the link. Public help/marketing pages are open; the live map requires a login.
Glossary
MESH
Maximum Estimated Size of Hail (radar estimate, inches).
MRMS
Multi-Radar Multi-Sensor — NOAA's national radar product MESH comes from.
Swath
The colored overlay: the day's max hail size everywhere radar saw it.
SPC report
A Storm Prediction Center hail report — an individual ground/spotter observation (the dots).
NEXRAD
The national Doppler radar network; the optional animated loop.
Troubleshooting
The map or swath looks slow / blank for a second
Give it a moment on first load while the day's data renders. If it persists, hard-refresh (Ctrl/Cmd+Shift+R). Zooming should be smooth.
"Trial or paid access required"
The hailed-addresses tool and lead exports need a trial or paid account. The map, dates, swath, hail reports, and click-to-inspect are available to any signed-in user.
No addresses came back in my circle
Either nothing met your hail threshold there (lower it), or — for scoped accounts — your click was outside your entitled states.
I think a hail estimate is wrong
Radar estimates aren't perfect. Cross-check the SPC report dots and nearby cells; the broad pattern is what to trust for canvassing decisions.